4. Patients that are on CYP3A4 inhibitors and cannot replace these medications with other equivalent medications for the period of study: protease inhibitors (ritonavir, indinavir, nelfinavir, saquinavir), some macrolide antibiotics (clarithromycin, telithromycin, erythromycin), azole anti-fungals (fluconazole, itraconazole, ketoconazole), metroclopramide, felodipine, nifedipine, carbamazepine, phenobarbital, grapefruit juice and St. John s Wort.